Immunocytochemical detection of prognostic markers in breast cancer; technical considerations.

The purpose of this study was to establish a good technical procedure for immunocytochemical (IC) staining of prognostic markers in breast cancer specimens. The influence of various preparation, fixation and storage methods on ER, P53 and Ki-67 IC staining was assessed, using cells of two breast cancer cell lines T47D (ER/P53+) and ZR-75-ER (ER+, P53-). In addition we searched for a suitable transport medium. Depending on the technical procedure, great variations in expression of the tested antigens were found. Cytospins fixed and stored according to the Abbott method gave the best results. Histocon appeared to be the medium of choice. A good concordance of IC and immunohistochemical (IH) results was found when the adopted method was tested on material of 10 breast cancers. This study underlines the importance of quality controlled standardization of cell processing, fixation and storage of fine needle aspiration (FNA) aspirates in order to obtain reproducible and consistent IC results.

Immunocytochemical staining of effusions; an external quality control study in The Netherlands.

In The Netherlands an external quality control study of immunocytochemical (IC) staining of effusions was initiated, consisting of three test rounds. The 12 participating laboratories received samples of malignant effusions (runs 1, 2 and 3), and five unstained control specimens prepared from the same material in runs 2 and 3. The laboratories used their own protocols to prepare and stain the samples ('in-house' specimens). Two persons viewed and scored the slides following preset criteria concerning number and morphology of diagnostic cells, background staining and staining specificity. Better scoring results were found for control specimens, compared with 'in-house' specimens, primarily caused by cell loss in the latter. This finding underlines the view that high quality IC needs well organized processing and staining procedures, and warrants external quality control systems.

Quality control of immunocytochemical staining of effusions using a standardized method of cell processing.

OBJECTIVE: To improve the quality and reproducibility of immunocytochemical staining of effusions by using a standardized method of cell processing. STUDY DESIGN: The study included the specimens of 108 effusions (44 benign, 56 adenocarcinoma metastases and 8 mesotheliomas). Hemorrhagic effusions were lysed using isotonic ammonium chloride. All pellets were fixed in 1% paraformaldehyde dissolved in phosphate-buffered saline (PBS), pH 7.4, and washed in PBS. A Burker counting chamber was used to adjust the pellets to a standard cell concentration. The panel of monoclonal antibodies (MAbs) included MOC-31, Ber-EP4 and anticarcinoembryonic antigen (anti-CEA). The alkaline phosphatase/anti-alkaline phosphatase technique was applied. RESULTS: Standardized material processing resulted in reproducible specimens with good preservation of cell morphology, reduction of nonspecific interaction and good immunostain intensity. MAbs MOC-31 and Ber-EP4 gave similar results: both were positive in all adenocarcinomas. Anti-CEA was positive in 73%. Benign effusions showed no expression. In contrast to the literature, seven mesotheliomas showed variable membranous expression of MOC-31 and Ber-EP4. CONCLUSION: High-quality immunostaining results were obtained by using a standardized method of cell processing. MAbs MOC-31 and Ber-EP4 cannot be used as differentiation markers between mesotheliomas and adenocarcinomas. Discrepancies in immunocytochemical staining results may be caused partly by differences in cell preparation.